1. Field of the Invention
The present invention is directed to using pneumatic orifices to tune a pneumatic manifold of a seeding machine to better distribute the air pressure between the various seed meters.
2. Description of the Prior Art
Modern seeding machines use sophisticated seed metering systems for controlling the rate at which seeds are planted. Many of these sophisticated metering systems use air pressure to control the application of seed to the ground. In one system positive air pressure is used. In other systems negative air pressure in the form of a vacuum is used to meter the seeds. This positive or negative air pressure is generated by an air pump in the form of a fan. This air pressure from the air pump is directed to a pneumatic manifold. The pneumatic manifold in turn is pneumatically coupled to the individual seed meters by hoses. The air pressure supplied to different row units is not identical. Such a condition results in uneven seed meter performance possibly resulting in variations in row-to-row seed populations and row-to-row seed spacing. The positive or negative air pressure is highest at those seed meters pneumatically closest to the source of pressurized air.